Description of Event or Problem · 1
THE PATIENT WAS ON CARDIOPULMONARY BYPASS WITH A PC02 OF 19 MMHG. SWEEP GAS FLOW WAS APPROXIMATELY 1.0 LPM. THE PERFUSIONIST ATTEMPTED TO RAISE THE PC02 LEVEL UTILIZING THE C02 GAS FEATURE OF MODEL 9000 CARDIOPULMONARY BYPASS SYSTEM ("PUMP"). BY DESIGN OF THIS SYSTEM, WHEN SWEEP GAS IN EXCESS OF 0.2 LPM IS FLOWING, THE FLOW OF C02 SHOULD NOT OCCUR WHEN REQUESTED. IN REALITY, THERE IS A NORMAL DELAY OF APPROXIMATELY 0.5 SECONDS FROM WHEN THE C02 GAS "ON" SWITCH IS PUSHED (C02 GAS FLOW BEGINS) AND WHEN THE SYSTEM DETECTS SWEEP FLOW AND TURNS OFF THE C02 GAS GLOW. APPROXIMATELY 33 CC'S OF C02 GAS IS ADDED TO THE SWEEP GAS EACH TIME THE C02 GAS "ON" SWITCH IS PUSHED (4LPM X 0.5 SECOND = .0333 L). THE FIRST ACTIVATION (SOMETIME BETWEEN 15:35 AND 15:40) RAISED PC02 FROM 19 MMHG TO 34 MMHG AS MEASURED WITH AN IN-LINE EXTRACORPOREAL CIRCUIT ANALYZER. THE LIGHT INDICATING THE FLOW OF C02 GAS HAD COME ON FOR APPROXIMATELY 0.5 SECONDS AND THEN WENT OFF AS IS NORMALLY EXPECTED. AFTER A SECOND ACTIVATION (APPROXIMATELY 1-2 MINUTES AFTER THE FIRST ACTIVATION), THE BLOOD WAS OBSERVED TO TURN DARK. PC02 GAS HAD AGAIN COME ON FOR APPROXIMATELY 0.5 SEONDS AND THEN WENT OFF AS IS NORMAL. BECAUSE OF A SOFT "HISSING" SOUND CHARACTERISTIC OF GAS FLOW, THE C02 "OFF" BUTTON WAS DEPRESSED WITH NO APPARENT EFFECT ON THE NOISE. THE C02 "ON" LIGHT REMAINED OFF. THE SWEEP GAS WAS THEN INCRESED TO 9LPM WITH AN FI02 OF 1.0. THE HYPOXIC EPISODE WAS RESOLVED BEFORE THE END OF THE SURGICAL PROCEDURE.THE PUMP WAS SUBSEQUENTLY FOUND TO INTERMITTENTLY CONTINUE THE FLOW OF C02 GAS EVEN WITH SWEEP GAS >0.2 LPM AND AFTER THE C02 GAS ACTIVATION LIGHT HAD GONE OFF. THIS OCCURRED FOR VARYING LENGTHS OF TIME, AS LONG AS UP TO FIFTEEN MINUTES (THE NORMAL TIME-OUT CYCLE FOR C02 FLOW WITH NO SWEEP GAS). THE PUMP IS IN THE PROCESS OF REPAIR BY MANUFACTURER.